The core of human abilities CEREBRAL · 2017. 9. 20. · - 500 samples per second x 64 electrodes x 60 minutes = 115,200,000 samples - Children: All difficulties multiplied by 10

1

Educational Neuroscience

Broadly defined:

The application of cognitive neuroscience methods

to learn about phenomena with educational relevance

- molecular

- cellular

- anatomical systems

- behavioural level

- mental proceses

(functions)

Cognitive

psychology

Cognitive

neuroscience

Our mental life and behaviour relies on the brain.

Neuroscience is the study of the nervous system

(including the brain).

The brain can be studied at many different levels:

The core of human abilities

Right View

Front Back

THE

CEREBRAL

CORTEX

Gyri

White matter

Sulci

2

Selective brain damage

Focal lesions

Accidents (e.g. forgotten languages, neglect)‏

FUNCTIONAL

LOCALIZATION

Hanna Damasio et al. Science 1994

FUNCTIONAL

LOCALIZATION

Neurons (Information processing units) & their communication Functional brain mapping Structural brain mapping

3

Somatotopic

Maps in the brain

TOPOGRAHIC MAPS Mental representation: Neural patterns in distributed networks of neurons

Hearing

Planning

Vision

Location

Objects

Movement

Body sens.

The main immediate function of neurons: signalling: Sending information around in networks.

Gazzaniga et al. 2002

Complex activities require the

Coordination of many representations

DISTRIBUTED PROCESSING – complex functions rely on many brain areas

+ (naturally) what you play....

& why you like it.... ???

Our mental life relies on brain structure and function Cognitive psychology:

Study of mental representations and operations on them: ‘The conceptual units of the mind’ How we structure and analyze the world in our mind.

Cognitive neuroscience:

relating hypothesized mental representations to brain structure and function in relation to mental representations and processes

Education: systematic shaping of human’s mental life (mental representations and processes)‏ Both Cognitive Neuroscience and Educational research are interested in the performance and plasticity of the human brain

Nevertheless, they study the brain at very different levels.

Is their relationship a bridge too far? (Bruer 1997)‏ The study of mental representations is useful for educational research as well.

When?

Cognitive Neuroscience and Educational Research

Szűcs & Goswami, 2007, Mind, Brain and Education

4

What is a mental representation? Wide definition: Pattern of neural (brain) activity enabling mental function Pattern of neural (brain) activity - coding entities of the world - neural processes transforming the above codes Representation: - code - and processes operating on these codes

Experimental design

(independent of all the fancy techniques)

is of PRIME importance

Magneto-encephalography (MEG)

Magnetically shielded room All metals removed No body piercing, Certain tooth fillings Bullets in body

Liquid helium

5

MEG vs. EEG Sensitive to differently oriented signals

MEG

EEG

Combination of methods:

Magneto-encephalography (MEG)

With

Electro-encephalography

(EEG)

Average electrical activity at one electrode

Time (milliseconds)‏

Voltage

(µV)‏

Baseline

0 200 400 300 100 -100 500

+3

-3

µV

-3 Stimulus

1 vs. 2

1 vs. 8

Szűcs & Soltész, 2008, Brain Research

The inverse problem in EEG and MEG

Poor spatial resolution with excellent

Temporal resolution

? Functional anatomical imaging:

- CT, CAT scan

- MRI: Magnetic resonance imaging: structural and functional

- PET: Positron emission tomography

6

An X-ray picture (radiograph), taken by Wilhelm Röntgen in 1896, of his wife, Anna Bertha Ludwig's hand

X-ray Chest X-ray

CAT-scan Computed Axial Tomography

CAT-Scan

7

PET Scanner

Brain: 2% of body mass; 20% of oxygen; max 10 mins tolerance to O loss

Radioactive Material in Blood

PET

Brain; rCBF: Regional Cerebral Blood Flow Assumption: more blood, more brain activity Blood: glycose (sugar) and oxygen

Whole body

MRI Scanner

Wikipedia.org

8

Functional Magnetic

Resonance Imaging

(fMRI)‏

&

PET

Mirror

MRI: Magnetic resonance imaging

Structural MRI 3D anatomical image of the brain

Measurement by usign strong magnetic field

MRI: 1.5 to 4.0 or 7.0 Tesla Earth: 5 × 10-5 (0.00005) Tesla

Measurement depends on different magnetic

properties of tissues

(e.g. Grey, White matter, blood vessles)


fMRI: functional MRI Measuring the oxygen content of blood by magnetic fields [MF]

Assumption: More oxygen is used where the brain is more active

(Oxygen is attached to Hemoglobine [HB] in blood)

Oxygenated HB repulses from MF (diamagnetic) De-oxygenated HB is attracted to MF (paramagnetic)

Magnetic suspectibility (intensity of magnetisation)

of de-oxygenated blood is 20% greater than that of fully oxygenated blood

Measuring the proportion of de-oxygenated and oxygenated blood

9


Structural MRI fMRI: functional MRI

fMRI is good to study anatomical hypotheses:

Where is something happening in the brain?

However, its temporal resolution is poor (seconds).

Neurons (Information processing units) & their communication Neurons (Information processing units) & their communication

10

Time (milliseconds)‏

Voltage

(µV)‏

Baseline

0 200 400 300 100 -100 500

+3

-3

µV

-3

Stimulus

Event-related brain potentials (ERPs)

Reaction Time

Time

(ms)‏

0 100 200 400 300 500

EEG signal differs hugely from fMRI signal

which measures blood flow (not direct neural activity)

fMRI: functional MRI

Measuring the oxygen content of blood by magnetic fields [MF]

Measuring the proportion of de-oxygenated and oxygenated haemoglobin in blood (BOLD signal) (Oxygen is attached to Hemoglobine [HB] in blood)

Assumption: More oxygen is used where

the brain is more active

Oxygenated HB repulses from MF (diamagnetic) De-oxygenated HB is attracted to MF

(paramagnetic) Magnetic suspectibility (intensity of magnetisation)

of de-oxygenated blood is 20% greater than that of fully oxygenated blood

ERP

fMRI

Temporal Resolution

WHEN

Spatial Resolution

WHERE

Good

1 millisecond or better

Bad

From half a second to

Several seconds

Good

Can be half a centimetre

Bad

From several centimeters

to unknown

EEGs vs. fMRI

The laboratory setting:

very different from a classroom setting! (ecological validity)

11

General methodological problems in the laboratory environment

- Laboratory settings (strange environment)‏

- Environmental noise (affecting the equipment or the subject)‏

-> Silent, deprived environment

- Subject noise (not environmentally induced)‏

- Performance fluctuations, strategy change (complex tasks)‏

- Movement (constrained settings), heartbeats, blinks

- Paradigm design

(unexciting and repetitive tasks)‏

- Large quantity of data must be analyzed.

- 500 samples per second x 64 electrodes x 60 minutes

= 115,200,000 samples

- Children: All difficulties multiplied by 10

When is neuroscience useful? When it can tell you something which cannot be Determined from behavioural data alone.

When is neuroscience useful for education research? When it can tell you something which cannot be determined from behavioural data alone. - Why is good to have neuroscience data? - What kind of neuroscience data should I have?

This depends on the strengths/weaknesses of methods. If you ask about anatomy, use fMRI If you ask about timing, use EEG

- Is the laboratory environment an appropriate model? (it is not for example, for studying classroom interactions) Below comes an example which demonstrates a situation When neuroscience data can deliver information that Cannot be determined from behavioural data....

12

The color-word Stroop task in Developmental research What is the INK color? A good model of Decision making With distraction Development: Response inhibition: An important skill Emerging through Development Direct impact on e.g. Control of behaviour In School. RED

YELLOW

RED

BLUE

BLACK

GREEN

RED

Stroop 1935

RED

RED Incongruent

Congruent

Stroop 1935

Classical color-word Stroop task: What is the INK color?

Stroop 1935

RED

Reading (naming color word)

Naming INK

Interference

Fast: OVERLEARNT

Slow

Basic model of the Stroop effect: Parallel processing

Time

RED

Congruent Incongruent CONDITIONS

REACTION TIME

Two main theories of typical behavioral results in Stroop task

Slowing down is due to... 1) Resolving conflict between perceptual/semantic features 2) Main source of conflict is incorrect response activation

13


REACTION TIME

Two theories of behavioral results in Stroop task


Children usually have larger Stroop effects than adults So, do children have worse... 1) Perceptual processing than adults? 2) Do they have worse motor control? Implications for educational practice!


REACTION TIME

Two theories of behavioral results in Stroop task


Children usually have larger Stroop effects than adults So, do children have worse... 1) Perceptual processing than adults? 2) Do they have worse motor control? Implications for educational practice!

Educational question: -Are children able to process cognitive/perceptual information as effectively as adults? - If they can; can they interface/use this information with the motor system effectively NOT POSSIBLE TO DECIDE BY BEHAVIOURAL METHODS ALONE

5-8 year-old children in the laboratory

Szűcs D et al. 2009. Journal of Cognitive Neuroscience.

The CHILD FRIENDLY experimental paradigm

Which animal is larger in real life? (Moyer, 1973)

Press the response button on that side (Animals were known to children; and rated as big or small by children)

Congruent

InCongruent

(conflicting)

Conditions

2 8

2 8


Press RIGHT

Press RIGHT

14

Quick

Size

decision

The animal Stroop paradigm

Congruent

Final,

Overt

Response Slow

Semantic

decision


Triggers

Correct response Hand

Note that only this decision

Was required by the experimenter

Triggers


Involuntary

Quick

Size

decision

Slow

Semantic

decision

Incongruent

Slower

Response


Conflict


Triggers

INCORRECT response Hand

Triggers


Note that only this decision

Was required by the experimenter

Involuntary

+3

-3

µV

Movement related cortical potentials: Information not accessible behaviourally

Time (ms)

The Lateralized Readiness Potential

(LRP)

to correctly responded trials

Size

decision

Semantic

decision

Conflict Response

Inhibition Monitoring

& Control

The Lateralized Readiness Potential (LRP) to correctly responded trials

Hypothetically EXPECTED


LRP in the Incongruent Condition

15

Lateralized Readiness Potential (LRP) to correctly responded trials

Congruent

Incongruent

Real Data Real Data

Hypothetically EXPECTED

LRP in the Incongruent Condition


Congruent

Incongruent

Real Data Real Data

Szűcs et al. 2009. J Cognitive Neuroscience

Perceptual processing Motor control

Bryce, Szűcs et al. 2011. NeuroImage


Conclusion: correction of incorrect motor tendency

is much slower in younger than older children

Educational questions

-Are children able to process cognitive/perceptual information as effectively as adults? - At least in the Stroop task context they can

- If they can; can they interface this information with the motor system effectively? - No, their efficiency is much worse than that of adults.

The above data could not be accessed by behavioral methods because you have to observe incorrect response activation explicitly. Hence, here EEG provides a unique possibility to collect data otherwise inaccessible for research which can inform practice. Classroom implications: Children may process some information perceptually but may be unable to act upon it effectively.

16

When is neuroscience NOT useful? When it can tell you nothing which is already not evident from the behavioural data. E.g. - The brain is the basis of our mental life > - The brain does everything > - From the point of view of education it is not too informative to show that a particular part of the brain does a particular function... (e.g. This may be important for a doctor, though...) - Provided you do not say anything else as already known from behavioural data... (However, it is ‘sexy’! .....)

Two main questions: 1. Why is this brain-based explanation interesting for me? (is it useful for me to know this?) A. It is interesting because I like to know more about the brain B. It is interesting because it is useful for me to know more

about education A does not equal B 2. Do I have the methodological knowledge to judge the value of a report?

Beware of the popular science press! BBC about the brain: 15:00 GMT, Tuesday, 14 October 2008 16:00

Documents

The core of human abilities CEREBRAL · 2017. 9. 20. · - 500 samples per second x 64 electrodes x 60 minutes = 115,200,000 samples - Children: All difficulties multiplied by 10